History of Monsters. 384 Ulisse Aldrovandi

Mercatus proposes a third form of the origin of monsters that depends on the defect of the matter—specifically, in the thickness, hardness, fluidity, or corruption of the seed and the menstrual blood. Because of this, the beings generated from it differ significantly from the nature of their parents. Weinrich identifies this as the fifth vice of matter, asserting that the generative power is so overwhelmed in thicker sperm that it cannot properly assist in the formation of the fetus. This typically occurs when the constitution of the testes is overly dry. Conversely, watery seed suffers from the opposite defect, which Weinrich calls the sixth vice of matter; such seed is rejected because, being too liquid, it is unable to solidify into nerves, veins, arteries, and subsequently into the other more solid parts of the body.

Now that we have discussed the departure from the parents' nature, it should be noted in passing that these monsters differ from the nature of their parents in three ways. First, while the matter of the seed is suitable, it is not entirely mastered. In such cases, things are created that can only achieve a general or generic likeness, since a specific or individual resemblance cannot result. Thus, an "animal" is created when a "human" cannot be, for nature always strives toward what is better but stops at what is possible. Therefore, due to a defect in the matter, only a sentient being is generated, and nature halts there; for while the seed possesses the potential for sensation, it reaches only that stage. A rational being is not formed, nor is such a soul introduced, because of the unsuitability of the material and its construction.

Second, offspring differ from their parents through a deeper deficiency, where the faculty of the seed is so hindered that not even an animal can be generated. Instead, only something shapeless is produced—a middle ground between the living and the non-living, such as the "molae" (fleshy masses) that women sometimes give birth to, which we discussed above in the Section on Differences. Finally, by this same defect, the matter is rendered so unfit that the power of the acting agent cannot transform it at all. From this arises what philosophers call things "entirely beyond nature" in their whole genus, such as when stones are generated within the womb.

Ambroise Paré brings forward a fourth form of the origin of monsters based on a defect in hereditary matter; in this way, hunchbacks are born to hunchbacks, and the scrofulous to the scrofulous. Weinrich supported this view, stating that certain deformities in monsters must be attributed to inheritance, as it is well known that dwarfs are born from dwarfs—though this is not always necessary nor does it happen in every case, for monsters of any kind do not usually multiply their own species.

The fifth form originates from something external happening to the pregnant woman, whether it be a fall from a height, a bruise, a wound, or any other injury of this kind that could harm the woman carrying the child. Weinrich demonstrates this when discussing injuries to the pregnant woman; indeed, he confirms his opinion with the authority of Hippocrates. In his book *On Generation*, Hippocrates declared that a child in the womb could become mutilated or bruised due to a blow to the pregnant mother, a fall, or some other violent incident. He affirmed that the fetus would be mutilated in the same part of the body where the mother received the bruise or wound.

The sixth and final form of the birth of monsters, in terms of matter, depends on the imagination. This force possesses the power to impede the material of the seed, preventing it from resembling the parents. Ludovicus Mercatus examines this method diligently, noting that there remains another obstacle by which the seed is prevented from acting freely or making the son resemble the parents: namely, a vehement and varied imagination. This occurs not only during conception but throughout the entire period of formation, for this shaping of the seed is dominated by the way lower powers obey the higher ones. Consequently, an image captured through a powerful imagination is imprinted on the fetus rather than the likeness of the father.

Saint Thomas agrees with this, asserting that the imagination is a power within a bodily organ, from which the bodily spirit—in which the formative power residing in the seed is fixed—is transformed into the imagined likeness. Therefore, a change sometimes occurs in the offspring because of the parent’s imagination during intercourse. From this it is clear that the spirit, moved by the imaginative power in the manner described, exerts its forces more effectively and outlines the form of the construction more than the formative power itself, which proceeds from the nature of the parents' limbs.

So great, then, is the power of the spirit of the shaping artisan that from a vehement imagination mi-